Controlling electromagnetic emissions from electronic equipment is of great concern in the design of highly sophisticated electronic equipment. The Federal Communications Commission has recently expanded the scope of its rules governing electromagnetic interference emissions from electrical equipment to include computing devices used in the home as well as in commercial, industrial or business environment.
Means for achieving electromagnetic compatibility include shielding, filtering and grounding. Shielding is used to minimize electromagnetic radiation. Filtering the system protects against conducted interference and protects low frequency communication signals by excluding high frequency noise. A proper grounding system is important particularly where there are multiple and electrically different power outlets used within the system. Improper grounding can adversely affect the equipment as well as create potential safety hazards.
Although shielded connectors and filtered connectors have been available for a number of years, there has been a recent increase in demand for these types of connectors and interconnecting devices. Separate shielding means and filtering means are used in many of today's equipment systems.
In addition there has been a demand for means to convert standard connectors into the type that can be used to make a shielded interconnection with a shielded connector and a cable. U.S. Pat. Nos. 4,337,989 and 4,386,814 disclose means for attaining such a conversion.
The filtered shielded connector assembly disclosed herein provides both filtering and shielding capabilities in a single unit, thus eliminating the need for separate devices. Furthermore, the invention provides a means for obtaining a greater number of terminals per given area than is possible with converted standard connectors. The invention also provides a grounding means directly through the connector. The herein disclosed invention provides an economical connector in terms of both space and cost savings.
A filtered shielded connector assembly is comprised of an insulated housing member, a plurality of pin terminals, a filtering means and a shielding means. The housing has a front face having one or more connector receiving openings therein, an oppositely facing back wall with a plurality of apertures therein, oppositely facing side walls, and oppositely facing end walls. The side walls and end walls extend from the front face to the back wall. The housing has one or more connector receiving cavities extending inwardly from said front face toward said back wall.
The shielding means is comprised of two members, a metal front face plate and a metal shell. The face plate has one or more openings therein, the number of openings being equivalent to the number of cavities in the housing. Each opening in the plate has one or more spring fingers which project rearwardly from the plane of the face plate. The metal shell has a rear wall with a plurality of terminal receiving apertures therein, opposing side walls and opposing end walls. The shell rear wall extends between the shell side walls and shell end walls, said walls defining a housing receiving cavity. The face plate and shell are dimensioned to surround the housing member when the assembly parts are joined.
The assembly has a plurality of pin terminals. The terminals have first and second ends, the first end passes through the apertures in the housing back wall and into the connector receiving cavities. The second terminal end extends rearwardly from the housing back wall, passes through a filtering means and the apertures in the shell's rear wall, and extend rearwardly from said shell wall. Fastening means are provided to join the parts of the assembly, thus forming a filtered shielded unit. The spring fingers on the shield face plate extend into the connector receiving cavities to provide shielding continuity with shielded plug connectors.
A better understanding of the invention is obtained by way of example from the following description and the accompanying drawings.